Pressure closure



Nov. 15, 1966 E. GOLDE PRESSURE CLOSURE Filed March 18, 1965 INVENTORERICH GOLDE ATTORNEY 3 United States Patent PRESSURE CLOSURE ErichGolde, Tattenkofener Strasse 4, Geretsried 8192, Upper Bavaria, GermanyFiled Mar. 18, 1965, Ser. No. 440,889 Claims priority, applicationGermany, Nov. 12, 1964,

Claims. (Cl. 215-40) This invention relates to bottle closures and moreparticularly to bottle caps for use on bottles containing carbonatedbeverages or other liquids which give rise to substantial pressureswithin the bottles in which they are contained.

It is known to use closure caps made of resilient thermoplastic resinsfor use on bottles or jars having an outwardly projecting crown or beadat their mouth. Such closures normally comprise principally asubstantially fiat main deck member to cover the mouth of a bottle and,downwardly depending from the periphery of the deck member, a skirtmember which is provided with an inwardly projecting retention beadwhichis adapted to become locked under the bead of the bottle. It isdifficult, however, to fabricate such closures so as to make themeffective for use on bottles containing carbonated beverages. The carbondioxide which is liberated at higher temperatures when the filledbottles are shaken while in transit results in a great increase-ininternal pressure and thereby tends to pop the closure off the bottle.Caps are known which somewhat reduce the effect of this internalpressure by confining it to a smaller area of cap by means of acircularsealing extension which depends from an intermediate portion of the deckof the cap and is adapted to fit tightly against the inside wall of thebottle month. However, even in such cases it is difficult to protect thecap against the effects of increased internal pressure because thenormal tolerance or variation of the external diameters of the bottlemouth places definite limits on the degree to which the wall thicknessof the skirt and of the retention bead, or the stiffness of the resinousmaterial, can be increased. This is particularly true when the closureis intended to be removable and replaceable by hand.

Furthermore, economic reasons make it desirable to avoid thick walls asthese increase the quantity of material required and result in longermachine operating times during fabrication.

This is where the present invention makes its surprising contribution.According to this invention the peripheral portion of the upper surfaceor deck of the cap and its skirt are grooved or perforated by two ormore narrow indentations or notches, preferably substantially oppositefrom each other, which end in the skirt approximately at the level ofthe retention bead, leaving the portion of the skirt below the retentionbead substantially unweakened. Tests have shown that closures providedwith such notches, grooves or perforations resist considerably higherinternal pressures than caps of equal wall thickness which do not havesuch notches. An explanation of this effect will be given later inconnection with the drawing.

The invention results in the further advantage in that the notches orperforations facilitate the removal of the cap from the bottle. Toprovide this additional advantage it is preferable to place the notcheson a diameter of the cap which is perpendicular to the diameter on whichthe lift tab is attached to the cap. Furthermore, the described notchessubstantially assist in compensating for the tolerance in the externaldiameter of the mouth of the bottle.

The invention can likewise be used for closures which, instead of theaforementioned sealing extension, contain a separate sealing insertadapted to protrude into the mouth of the bottle. Such a two-componentconstruction is particularly advantageous when the bottle is intendedfor opening by hand. In such a case it is possible to make the sealinginsert from a softer resin than the cap itself and thereby facilitateplacement and removal of such caps on bottles as well as compensationfor any large tolerance in the inside wall of the bottle. It isparticularly advantageous to equip such sealing inserts with a hollowseal ring. Furthermore, it is possible to attach such a sealing insertto the cap by fusion in the middle of the main deck of the cap andthereby facilitate the eventual removal of the closure from the bottle.

In the attached drawing:

FIGURE 1 is a section taken along lines A-B of the cap shown in FIGURE2;

FIGURE 2 is a plan view of one embodiment of a cap embodying the presentinvention;

FIGURE 3 shows the cap illustrated in FIGURES 1 and 2 in place on abottle, viewed from B and in partial section;

FIGURE 4 is a schematic drawing presented to illustrate theaforementioned retention effect;

FIGURE 5 is a section taken along lines C-D shown in FIGURE 6; and

FIGURE 6 is a plan view of another embodiment of the invention.

FIGURES 1 and 2 show the cap with its main surface or deck 1, skirt 2and an annular sealing extension member 3 protruding downwardly from anintermediate portion of deck 1. Skirt 2 is provided with an inwardlyprojecting retention bead 4 which is adapted to reach under the externalbead or lip 5 of the bottle as shown in FIGURE 3. Notches or grooves 6are formed in the periphery of deck 1 and extend down into skirt 2approximately to the level of retention bead 4 so that only relativelythin inner skin 7 remains. When such a skin is completely absent thenotches become slots or perforations, but a tight seal with the bottleis nevertheless effected by means of inner seal member 3.

Referring to FIGURE 3, the arrow V is intended to indicate the directionof the internal pressure acting on the underside of the cap deck,causing the originally flat surface of the deck to become slightlyarched. The retention bead 4 is pressed by the resulting pincer actionmore tightly into the recess or hollow 8 under bead 5 of the bottle asfurther shown in schematic FIGURE 4. The notches 6 divide the main deck1 of the cap into segments 9 and 10 which are connected hinge-like toeach other by means of the bridge 11 remaining along the diameterextending between two opposite notches 6. The force acting on segments 9and 10 in the direction of the arrow presses the retention beadpincer-like by means of skirt 2 in the direction of the horizontalarrows H into recess 8 on the bottle neck. The increased inner pressurecaused by liberated carbon dioxide thus increases the retention pressureof the retaining head in a cap formed in accordance with the presentinvention. In addition, the aforementioned hinge 11 has been found tofacilitate the removal of the closure as Well as helping to overcome anysubstantial variations in bottle wall thickness.

The cap shown in FIGURES 5 and 6, instead of being provided with anintegral sealing extension, contains a separate sealing insert 12 whichis adapted to protrude into the bottle by means of its annular sealingmember or hollow ring or plug 13. The central portion of the sealinginsert embraced within the inner wall of the hollow ring abuts deck 1 ofthe cap from below and may be fastened to the latter by fusion. Thisfacilitates subsequent opening of the bottle by hand. When the cap islifted off the bottle by pressure of the thumb under the lift tab 15 thehollow sealing ring 13 at first remains wedged in the mouth of thebottle until the retention bead 4 begins to unlock and only continuedlifting of tab 15 will cause the sealing ring or plug to be pulled fromthe bottle by means of the fused connection 16. When a tamper-proof capis desired, lift tab 15 may be in the form of a downwardly open pockethaving a sturdy front member serving as the actual lift tab and thin,frangible or tearable side walls or portions 17 through which the lifttab is connected to the skirt and which are torn when the tab is firstlifted to open a fresh bottle.

While the cap shown in FIGURES 1 and 2 contains one pair of notches itwill be observed that the cap shown in FIGURE 6 contains two pairs ofnotches or indentations 6.

It should be understood that several embodiments have been described toillustrate the invention, but that the latter is not intended to belimited thereby. For instance, it is possible to provide the separatesealing insert, in addition to the plug 13, with an outer skirt or coverwhich is adapted to totally or partially embrace bead on the bottle, inwhich event this skirt can carry its own inwardly projecting retentionbead. In such a case the retention bead 4 of the cap should be adaptedto extend this skirt of the sealing insert. It is likewise possible,instead of a continuous retention bead 4, to provide a plurality ofsmall retention knobs or protuberances of appropriate thickness orrigidity permitting them to lock firmly under bead 5 of the bottle.

The invention for which protection is desired is particularly pointedout in the appended claims.

The claimed invention is:

1. A bottle cap of thermoplastic resin adapted for use with a bottlehaving an external bead near its mouth, which cap comprises a deckmember, an outer skirt member, an internal sealing member adaptedv toabut the inside of said mouth, and a retention bead projecting radiallyinwardly from said skirt and adapted to become locked under saidexternal bead of the bottle, said deck and skirt members having in theirouter peripheral portending from saidvdeck member downwardly into saidskirt member to about the level of said retention bead, saidindentations terminating short of the skirt bottom.

2. A resilient thermoplastic cap adapted for use on a bottle'haviug anoutwardly projecting bead near its mouth, which cap comprises asubstantially flat circular deck member, a cylindrical skirt memberattached to said deck member at the periphery thereof, a retention beadprojecting from said skirt member radially inwardly, a sealing memberadapted to extend into the mouth of a bottle, and a lift tab attached tothe cap near the periphery thereof, said deck and skirt members havingin their outer peripheral portions at least two groove portions locatedopposite each other along a diameter of said deck member and extendingfrom said deck member downwardly into said skirt member to approximatelythe location of the retention bead thereon.

3. A cap according to claim 2 wherein said groove portions are arrangedin a plurality of opposite pairs.

4. A grooved cap according to claim 2 wherein said lift tab is attachedto said cap at a point which is located on a diameter perpendicular to adiameter on which two of said groove portions are located.

5. A grooved cap according to claim 2 wherein said lift tab is connectedto said skirt member by a frangible connecting member which ruptureswhen the tab is lifted to raise the cap ofl? a bottle.

References Cited by the Examiner UNITED STATES PATENTS 2,156,258 5/1939Atwood 215-46 X 2,987,206 6/1961 Grussen 21541 X 3,142,404 7/1964 Krieps215-46 FOREIGN PATENTS 895,512 5/ 1962 Great Britain.

JOSEPH R. LECLAIR, Primary Examiner.

D. F. NORTON, Assistant Examiner.

2. A RESILIENT THERMOPLASTIC CAP ADAPTED FOR USE ON A BOTTLE HAVING ANOUTWARDLY PROJECTING BEAD NEAR ITS MOUTH, WHICH CAP COMPRISES ASUBSTANTIALLY FLAT CIRCULAR DECK MEMBER, A CYLINDRICAL SKIRT MEMBERATTACHED TO SAID DECK MEMBER AT THE PERIPHERY THEREOF, A RETENTION BEADPROJECTING FROM SAID SKIRT MEMBER RADIALLY INWARDLY, A SEALING MEMBERADAPTED TO EXTEND INTO THE MOUTH OF A BOTTLE AND A LIFT TAB ATTACHED TOTHE CAP NEAR THE PERIPHERY THEREOF, SAID DECK AND SKIRT MEMBERS HAVINGIN THEIR OUTER PERIPHERL PORTIONS AT LEAST TWO GROOVE PORTIONS LOCATEDOPPOSITE EACH OTHER ALONG A DIAMETER OF DECK MEMBER AND EXTENDING FROMSAID DECK MEMBER DOWNWARDLY INTO SAID SKIRT MEMBER TO APPROXIMATELY THELOCTION OF THE RETENTION BEAD THEREON.